I just finished (literally 20 min ago) a hydraulic tensioner upgrade to my 02 FLHT. While I was in there I went ahead and upgraded to Andrews TW37 cams and inner cam bearings. I did not pull the heads. I replaced the push rods with adjustables push rods. Everything went reasonably well. I cranked it up and after some lifter ticking (that freaked me the F out) for about 1-2 minutes, everything quieted down.
It seems to be running fine except I hear some knocking in the carb. It's not lifter knock and I seem to have good oil pressure (engine light is not on). It's more like a brass hammer lightly tapping a peice of really hard wood like solid maple. It only does it at low RPM. As I increase the revs up past 1500 if fades out as the engine comes up. I thought it might me my air cleaner. Thinking it was loose, but I took that off and it is still doing it. I even put my ear up the the carb and it is definatly coming from there. The knock might have even been there before the upgrade an I am just being hyper sensitive after digging so deep into my motor. Carb is an S&S -E for what it's worth. Any ideas?

Here is a link to a video of the knocking. It's actualy not anywhere near as loud as the video makes it seem. http://www.youtube.com/watch?v=N4xFEVkYgII

 

Correction ---- The knock is back... Old post>>> I readjusted all the pushrods and found that my front exhaust was just a tad loose but not much. I let the lifters bleed down for an hour before firing it up. When I first cranked it up I still heard the knock but not as bad. I let it idle a little while until it was somewhat warm (5 min or so) and the knock is gone. I think it just didn't have enough time get oil everywhere in the top end before I freaked out.

I thought about deleting this post since no one responded but maybe it will help somebody else out who is going through the same thing I did and maybe keep them from loosing their mind.

 

Did you replace the lifters with that cam ? sounds like you might have a weak one not pumping up the same as the others and if new lifters (or even the old ones that had been sitting while you did the job) did you pre lube them ? pump them up with oil before inserting them ?

 

Thanks for the reminder! The knock is still there. I did NOT pre lube them before I put them back in and I know better. I'll bet it is the lifter(s) is where the noise is coming from. I am going to recheck with a long screwdriver to my ear tonight.

 

When it does pump up you will have to readjust the pushrods if it goes away after adjusting and then comes back after a couple of medium to hard runs you have a bad or weak lifter.....replace them all

 

Already searching for some 18538-99B's. So far all I can find are -99C's which (from my understanding) the -99B's are far superior to the new -99C's

 

So I have a similar sounding knock. Is coming from inside the carb. Side note carb is an S&S Super E. With a stethoscope it sounds like it's coming from the bottom of the butterfly. Did you ever find a solution?

 

The OPs noise sounds like intake reversion; annoying but not damaging. Very common with the Andrews 57 which has the identical profile as the 37 but more lift. Some aftermarket cam profiles with some aftermarket exhaust systems have some reversion which presents as a "thwok" more than a "knock" and with an open (hi flow) intake, the noise comes from the throttle body or carb. A dyno tune may reduce or eliminate the noise. A set of ear plugs is another option or just live with it; it's not hurting anything.:icon_wink"

 

Thanks dji, JB is my son and we have been trying to figure it out for a week or two. I believe his lower end is stock, '99 FXST? that we re-ringed. that's when the sound appeared. Going to recheck pushrod adjustment, and lifters.

 

My previous reply was related to the OP; not saying JB's noise is the same since I don't know motor components.

When you re-ringed, were the cylinders bored and new pistons fitted or just a hone and re-ring? Depending on miles, if the fix was a hone and re-ring, cylinders bores may not be true; ring installed upside down, poor piston to cylinder fitment as well as pushrod/lifters. Did you check compression or leak down before the re-ring?